The world of Zero no Tsukaima is an unusual example; it is its own independent world (albeit one with magic), but technically qualifies as this because they keep stealing our stuff (its easier than inventing stuff themselves), and they occasionally get some of our people too, who are Trapped in Another World as a result.

Fantastica ("Fantasia" in the film) from The Neverending Story. Bigger than the real world, however - in fact, as the home of everything ever created by the human imagination, it's supposed to be infinite and still growing.

Xanth has a lot of elements of this. And it's smaller than the real world due to it being a peninsula of some Earth continent (which one depends on the era, 'modern' Xanth is found mostly off Florida).

In Annyseed the magical land is not so much a secret, but goes unnoticed if you aren't looking for it. It surrounds the real world (which in itself, doesn't quite seem like reality), but the most magical area in Annyseed ’s version of the isle of Skye, is the woodland of Skull Valley, which works as a kind of Monster Town.

'Luddite' really isn't the right term to describe the people of the Wood. They widely use the Ethereal designs that seem to lose effectiveness if studied too carefully. Hence, the philosophy of the Court, which is to discover how the universe works is detrimental to them, setting them up in conflict.

The character of Erro from Interdimensional Transfer Student Erro comes from one of these realms - Another Dimension, of course, which is populated by a single species of strange, talking mascot animals (of which he is one).

Aylia, the titular character of A Magical Roommate, comes from Umbria. This is a bit of a subversion, however; Umbria is just a country in a much larger world, and the only off-worlders that affect politics are understandably those who married royalty. The jury is out on expanding technology, though.

The (non-Earth) planet in Guts and Sass: An Anti-Epic which features paleolithic to Iron Age technology, giant shapeshifting cats, anthropomorphic bodies of water, extrasensory abilities, a feudal monarchy, semi-domestic pastoralists, and hunter-gatherers.